Please Whitelist This Site?

I know everyone hates ads. But please understand that I am providing premium content for free that takes hundreds of hours of time to research and write. I don't want to go to a pay-only model like some sites, but when more and more people block ads, I end up working for free. And I have a family to support, just like you. :)

If you like The TCP/IP Guide, please consider the download version. It's priced very economically and you can read all of it in a convenient format without ads.

If you want to use this site for free, I'd be grateful if you could add the site to the whitelist for Adblock. To do so, just open the Adblock menu and select "Disable on tcpipguide.com". Or go to the Tools menu and select "Adblock Plus Preferences...". Then click "Add Filter..." at the bottom, and add this string: "@@||tcpipguide.com^$document". Then just click OK.

Thanks for your understanding!

Sincerely, Charles Kozierok
Author and Publisher, The TCP/IP Guide


NOTE: Using software to mass-download the site degrades the server and is prohibited.
If you want to read The TCP/IP Guide offline, please consider licensing it. Thank you.

The Book is Here... and Now On Sale!

Get The TCP/IP Guide for your own computer.
The TCP/IP Guide

Custom Search







Table Of Contents  The TCP/IP Guide
 9  TCP/IP Application Layer Protocols, Services and Applications (OSI Layers 5, 6 and 7)
      9  TCP/IP Key Applications and Application Protocols
           9  TCP/IP File and Message Transfer Applications and Protocols (FTP, TFTP, Electronic Mail, USENET, HTTP/WWW, Gopher)
                9  TCP/IP Electronic Mail System: Concepts and Protocols (RFC 822, MIME, SMTP, POP3, IMAP)
                     9  TCP/IP Electronic Mail Message Formats and Message Processing: RFC 822 and MIME
                          9  TCP/IP Electronic Mail Standard Message Format: RFC 822

Previous Topic/Section
TCP/IP Electronic Mail Standard Message Format: RFC 822
Previous Page
Pages in Current Topic/Section
1
23
Next Page
TCP/IP Electronic Mail RFC 822 Standard Message Format Header Field Definitions and Groups
Next Topic/Section

TCP/IP Electronic Mail RFC 822 Standard Message Format Overview, Structure and General Formatting Rules
(Page 1 of 3)

The primary protocol for delivering electronic mail is the Simple Mail Transfer Protocol (SMTP). For this reason, the message format used for TCP/IP e-mail could be considered SMTP's “protocol message format”, not unlike the special message formats discussed for other protocols, such as IP and TCP. However, the TCP/IP e-mail message format is used not only by SMTP but by all protocols and applications that deal with electronic mail. This includes the mail access protocols POP3 and IMAP, as well as others. It was also intended to potentially be usable by other non-TCP/IP mail delivery protocols.

Perhaps for this reason, the TCP/IP e-mail format was not specified as part of the SMTP itself, RFC 821, but rather in a companion document: RFC 822. Both were published in 1982. No official fancy name was given to this message format, and as a result the format became known by the name of the standard itself: the RFC 822 message format.

Development of the RFC 822 Message Format Standard

The history of the message format used in TCP/IP goes back long before 1982, of course. It was originally defined as the format for passing text messages on the Internet’s precursor, the ARPAnet, in the early 1970s. Over time the format was refined several times, leading to the publication, in 1977, of the important e-mail standard RFC 733 (Standard for the Format of ARPA Network Text Messages). RFC 822 later streamlined the contents of RFC 733, removing some of the features described in the earlier standard that failed to gain acceptance, and simplifying the specification.

In 2001, both SMTP and the RFC 822 message format were revised; SMTP is now described in RFC 2821 and the message format in RFC 2822. This newer standard makes relatively small changes to the RFC 822 message format to reflect modern use of TCP/IP e-mail. Even though RFC 2822 is the current standard, the original name is still the one most commonly used. I will respect that convention in this discussion, describing the message format based on RFC 2822 while still calling it the “RFC 822” message format.

The RFC 822 format describes the form, structure and content of TCP/IP electronic mail messages. It is, as I said, analogous to the message formats used for other protocols in TCP/IP. Like those other formats, the RFC 822 format can be logically divided into two main sections: the message header, which contains important control and descriptive information, and the message body or payload, which carries the data.


Previous Topic/Section
TCP/IP Electronic Mail Standard Message Format: RFC 822
Previous Page
Pages in Current Topic/Section
1
23
Next Page
TCP/IP Electronic Mail RFC 822 Standard Message Format Header Field Definitions and Groups
Next Topic/Section

If you find The TCP/IP Guide useful, please consider making a small Paypal donation to help the site, using one of the buttons below. You can also donate a custom amount using the far right button (not less than $1 please, or PayPal gets most/all of your money!) In lieu of a larger donation, you may wish to consider purchasing a download license of The TCP/IP Guide. Thanks for your support!
Donate $2
Donate $5
Donate $10
Donate $20
Donate $30
Donate: $



Home - Table Of Contents - Contact Us

The TCP/IP Guide (http://www.TCPIPGuide.com)
Version 3.0 - Version Date: September 20, 2005

© Copyright 2001-2005 Charles M. Kozierok. All Rights Reserved.
Not responsible for any loss resulting from the use of this site.